From what I can see, no purchase required, Myer is giving out free chocolate blocks for World Chocolate Day. Perhaps someone who has been there today can comment. Check link for details, but a sample of the blurb is below:
“To create more moments of connection, CADBURY DAIRY MILK has also partnered with MYER nationwide to surprise Australians this World Chocolate Day only by sampling 180g Milk Chocolate blocks on World Chocolate Day across stores nationally, so get down to your local Myer store on the 7 July to not miss out! *While Stocks last. One per person. Provided to 16+/guardians only”
Eastgardens Myer. Big stand of them and they giving one to everyone who walks by saying "world chocolate day, free blocks of chocolate"